Gold exploration company Challenger Gold has announced that the company’s recent metallurgical testwork program at the Hualilan Gold Project in Argentina, conducted in November 2023, has opened new avenues for the processing and profitability of the project.
The initial scoping study for the project outlined a process path yielding three primary product streams: an Au-Ag concentrate from bulk flotation, a Zn-Au-Ag concentrate from sequential flotation, and Au-Ag doré from leaching of the flotation tailings-leach (FTL).
A significant enhancement was identified late in the study’s preparation phase, proposing the conversion of the Au-Ag concentrate into doré through a fine-grind and high-intensity cyanide leach circuit.
This addition, although not fully supported by test work at the time of the study’s release, promised substantial improvements.
The conversion of Au-Ag concentrate to doré on-site is projected to eliminate transport costs of US$150 per tonne and treatment costs/refining costs (TC/RCs) of US$100 per tonne.
This process is expected to increase the payability of gold from 95 per cent to 99.5 per cent and silver from 60 per cent to 97.5 per cent, significantly enhancing the project’s revenue potential.
Two intensive leach tests conducted by SGS Lakefield on representative samples of the Au-Ag concentrate showed promising results: a 96 per cent recovery of gold for the 16.7 µm P80 grind sample and a 92.8 per cent recovery for the 40 µm P80 grind sample.
CEL Managing Director Kris Knauer said: “The testwork demonstrates a clear and simple pathway to produce gold doré on site which has several benefits for the project.
“Firstly, it removes some $100 million in costs associated with the transport and treatment of Au-Ag concentrate.
“Secondly, it increases the payability on the gold produced and removes the delay associated with payment for gold sold via a concentrate reducing working capital requirements.”
The capital expenditure (CAPEX) required for producing doré using this method is expected to be minimal, especially considering the low tonnage of Au-Ag concentrate needing fine grinding and intense leaching.
Operating costs are anticipated to be significantly lower than those associated with transporting and treating the Au-Ag concentrate.
This approach to upgrading the Au-Ag concentrate to doré is expected to generate considerable additional revenue and cost savings for the Hualilan Gold Project.
The results from the Hualilan Gold Project’s metallurgical testwork represents progress in the company’s pursuit of sustainable and profitable mining practices.